Hi BPC Team, We have a question regarding the definitions of the start_date and stop_date columns in the data_timeline tables (tables such as: data_timeline_imaging, data_time_treatment, etc.). These start_date and stop_date column values appear to be populated with integers but we are unsure as to the units of these integers and what their reference index point of 0 represents. Additionally, there are some instances of start_date being populated with a value but a null value in stop_date - and we would like some clarification on how to interpret these findings. Thank you!

Created by maayanbaron
Dear @maayanbaron, We follow the Timeline Data format as described by the cBioPortal Docs (see [here](https://docs.cbioportal.org/file-formats/#timeline-data)). Per the documentation: * START_DATE: the start point of any event, calculated in *days from the date of diagnosis (which will act as point zero on the timeline scale) * STOP_DATE: The end date of the event is calculated in days from the date of diagnosis (which will act as point zero on the timeline scale). If the event occurs over time (e.g. a Treatment, ...) the STOP_DATE column should have values. If the event occurs at a time point (e.g. a Lab_test, Imaging, ...) the STOP_DATE is still mandatory, but the values should be blanks. Let me know if this helps!

Clarification on start and stop date definitions in Data_timeline tables page is loading…